FIGURE 3 in Positive allometry for exaggerated structures in the ceratopsian dinosaur Protoceratops andrewsi supports socio-sexual signaling

FIGURE 3. Measurements taken from skulls of Protoceratops based on an idealised adult in dorsal view (above) and lateral view (below). Black lines and numbers indicate the measurements taken according to the variable of Dodson (1976). These are: 1, basal skull length; 2, total length (frill length is variable 2 subtracted from variable 1); 8, jugal width; 9, frill width; 13, orbit length; 14, orbit height. The grey lines indicate the maximum and minimum lengths of the frill as measured in juvenile animals. See text for further details.